Method and apparatus for opening folded box blanks

Abstract

The present invention relates to a method and apparatus for opening folded box blanks so that the opened blank can be filled. Apparatus of one embodiment of the invention comprises a substantially cylindrical cam having an axially and radially progressing spiral cam surface and a plurality of elongated transport screws for supplying, one at a time, folded box blanks to one end of the cam. The blank is opened upon rotation of the cam.

We claim: 
     
       1. A device for opening folded box blanks comprising: means for supplying the blanks comprised of rotatably mounted screw means for axially advancing the blanks upon the rotation thereof; and   cam means for directly receiving said blanks one at a time and for opening the received blank upon the rotation of said cam means about an axis of rotation.   
     
     
       2. A device as claimed in claim 1 wherein said cam means comprises a substantially cylindrical cam having an axially progressing spiral cam surface whereby a folded blank is received at a first end of said cam and is engaged along one edge thereof by said cam surface. 
     
     
       3. A device as claimed in claim 2 wherein the radial dimension of said cam surface from the axis of rotation increases as a function of an increasing axial dimension from said first end. 
     
     
       4. A device as claimed in claim 3 wherein said cam means completely opens the supplied folded blank in one 360° revolution of said cam and said cam surface has a minimum radial dimension at a 0° position and a maximum radial dimension at a 360° position, and wherein said supplying means supplies the folded blanks one at a time such that a folded edge of the blank engages said cam surface at said 0° position of said cam at said first end thereof and such that said blank is substantially perpendicular to said axis of rotation in both a vertical plane and a transverse plane. 
     
     
       5. A device as claimed in claim 4 wherein the dimensions of said cam are such that the difference between the maximum and the minimum radial dimensions of said cam surface from the axis of rotation is substantially equal to the difference in the width of a supplied folded box blank and the width of an opened box blank, and the axial length of said cam surface at said 360° position is substantially equal to the width of an opened box blank. 
     
     
       6. A device as claimed in claim 1 wherein said screw means comprises a plurality of spaced apart rotatably mounted, elongated screws for retaining and advancing a plurality of blanks, each screw having threads of a size and pitch such that one of the blanks can be retained between adjacent screw threads said blanks being axially advanced upon the rotation of said screws; and further comprising means for synchronously rotating said plurality of screws.   
     
     
       7. A device as claimed in claim 6 wherein said plurality of screws at least include a first screw and a second screw located on respective sides of the blanks; and wherein said cam means includes a cam mounted on and rotated with one of said first and second screws. 
     
     
       8. A device as claimed in claim 7 wherein said cam means comprises an elongate cam which includes an axially progressing spiral cam surface with a radial distance from the axis of rotation that increases as a function of an increasing distance along the axis of rotation and whereby a folded blank is received at a first end of said cam and is engaged along one folded edge thereof by said cam surface, the other folded edge of the blank being engaged and retained by said other of said first and second screws, whereby upon rotation of said cam the blank is opened. 
     
     
       9. A device as claimed in claim 1 wherein said supplying means further includes a storage means for storing a plurality of blanks and a transfer means for transferring the blanks from said storage means to said screw means. 
     
     
       10. A device as claimed in claim 9 wherein said storage means comprises a magazine having a slanted back for storing a plurality of blanks in a vertical pile, a plurality of feed rollers for receiving and advancing the bottom one of the blanks in the pile, and vibrator means for vibrating said back to advance the blanks in the pile such that a blank is always in contact with said feed rollers. 
     
     
       11. A device as claimed in claim 9 wherein said transfer means comprises a loading plate positionable between a first horizontal position whereby a blank is received from said feed rollers and a second vertical position whereby the blank is positioned for pick up by said screws. 
     
     
       12. A device as claimed in claim 1 wherein said screw means comprises at least one transport screw and wherein said cam means comprises at least one cam, said cam being mounted coaxially with said transport screw at one end thereof. 
     
     
       13. A device as claimed in claim 12 wherein said cam is integrally connected to and rotated with said transport screw. 
     
     
       14. A method of mechanically opening folded blanks having a plurality of folded edges comprising the steps of: supplying a plurality of blanks to a rotatably mounted screw means for axially advancing the blanks upon the rotation thereof;   rotating said screw means so as to directly present the box blanks one at a time to an opening means comprising a cam and a holding means;   engaging a first folded edge of the blank with said cam;   engaging a second folded edge of the blank with said holding means for holding the second edge of the blank;   and rotating said cam whereby the folded box is increasing compressed at one folded edge with the rotation of said cam and held at the other folded edge, thereby opening said blank.   
     
     
       15. A method as claimed in claim 14 wherein said screw means comprises an elongated screw and said cam and said screw are axially aligned and rotated together so that while said cam is opening one blank, a second blank is being advanced toward said cam. 
     
     
       16. A method as claimed in claim 15 wherein the blank is opened upon one rotation of said cam.